Preparation of quasi-two-dimensional Bose mixture of ultracold $^{23}$Na and $^{87}$Rb atoms

TL;DR

This paper reports the successful creation of a quasi-2D heteronuclear quantum degenerate mixture of ultracold $^{23}$Na and $^{87}$Rb atoms, enabling exploration of exotic quantum phenomena in low dimensions.

Contribution

The authors designed and implemented a compact, modular apparatus for preparing and studying a quasi-2D heteronuclear Bose mixture with detailed procedures and unique features.

Findings

Achieved quantum immiscibility in the 2D mixture.

Density profiles match mean-field theoretical predictions.

Established a versatile platform for low-dimensional quantum studies.

Abstract

Quantum gases confined in reduced dimensions have enabled the observation of many exotic quantum phenomena. While existing experiments primarily focus on homonuclear systems, we report here on the efficient preparation of a quasi-two-dimensional (2D) heteronuclear quantum degenerate mixture of ultracold $^{23}$Na and $^{87}$Rb. We describe the design of the vacuum system and detail the experimental procedures for preparing the 2D quantum mixture. The designed apparatus has several unique features, including compact and modular 2D-MOT sources, a science chamber that accommodates various lattice geometries, a precision in-vacuum electrode assembly, and high-resolution imaging for both atomic species. After loading the dual-species condensate into a single layer of a vertical optical lattice, we prepare a 2D gas mixture and observe quantum immiscibility in the in-situ equilibrium density profiles. The observed density profiles agree well with mean-field theories. The apparatus provides a versatile platform for investigating several interesting problems, including quantum impurities, quantum droplets, or polar molecules in low dimensions.